#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
int main()
{
	int arr[10] = { 0 };
	for (int i = 0; i < 10; i++)
	{
		scanf("%d", &arr[i]);
	}
	double ag;
	int sum=0;
	for (int i = 0; i < 10; i++)
	{
		sum += arr[i];
	}
	ag = sum / 10.0;
	printf("%lf ", ag);
	return 0;
}